Hillary Clinton's former press secretary Brian Fallon lashed out against Donald Trump and the president-elect's tweets saying they are just "the latest indication that (he) is someone very insecure in his victory."

Fallon's comments came during an interview on CNN's "New Day" program.

"Every day there are new developments, new shoes dropping so to speak, that call into question legitimacy of his win," Fallon said. "So, I think Donald Trump is just trying to cling to whatever legitimacy still is in effect here."

He said the Trump team first tried to deny Russian interference in the election. "Now they've been forced to admit that," he said.

Then the Trump team tried to say it was not done for the purpose of trying to help win the election.

"Now folks in the government have concluded that it was actually to try to tip the election Donald Trump's way," he said.

Fallon said he believed FBI Director Jim Comey's actions during the campaign relating to her use of a personal email server played a significant part in her defeat. He welcomed the announced internal review of Comey's actions relating to Clinton.

"The only thing to get to the bottom of these two issues are independent investigations," he said.

"We need the Department of Justice investigation into Russia to proceed in an independent manner. I'm not confident the incoming Attorney General Jeff sessions could lead it. It probably needs a special prosecutor and Congress needs a select committee.

"With respect to the DOJ, we need this independent watch dog investigation to proceed unimpeded," he added.

"I think it's very important that we in the public should all be interested in holding the trump administration's feet to the fire for it not to interfere with this review. Let it go forward and let's see what they have to say…"